The molecular biology of SV40. Our specific aims are to: a. determine what nucleotide sequences are involved in initiation and termination of early and late transcription, (i.e. the promoters and terminators) and what factors influence the selective expression of these transcriptional signals. b. determine what nucleotide sequences are involved in RNA splicing and, subsequently, the nature of the RNA substrates and enzymes needed for splicing. c. determine the function of leaders and splicing in mRNA biogenesis, particularly, if leaders and intervening sequences function in transcriptional or translational regulation. d. determine if the positioning and/or nucleotide sequence of structural genes and intervening sequences influence their processing and expression. SV40 transducing vectors for study of gene expression. Our specific aims are to: a. develop an array of SV40-based vector-host systems for transducing specific genes into mammalian cells. Such vectors should be capable of being propagated as 1) virions 2) integrated elements in mammalian chromosomes and 3) autonomously replicating plasmids. b. use such recombinant genomes to explore a range of basic questions concerning mechanisms of gene expression e.g. transcription, termination and polyadenylation, splicing, capping and translation etc. (See specific aims la-d above.) c. construct transducing vectors whose maintenance can be selected for in appropriate cultured cells. d. introduce human and/or rabbit genomic and cDNA segments that code for normal and genetically altered forms of alpha- and beta globin-like proteins (e.g. alpha and IV (alpha-like) and beta, delta, gamma and epsilon (beta-like)) into vectors of the type mentioned above to correlate structural and developmental parameters with their expression in the transduced cell. e. construct SV40 recombinant genomes containing rat genomic insulin gene I and the cDNA coding for human pituitary growth hormone to determine whether the precursor polypeptides are formed, processed properly and secreted in cultured cells.